Carb sync

[Ballast]

Hi all, does anyone have a carb balancing tool I could borrow for 4 cylinder bike, or could balance the carbs for me. The bike can be difficult to start and keep running on tick over, and runs runs extremely rough over about 6000rpm, revs OK upto there but sticks and struggles to get past. The bike also smells very strongly of petrol from the exhaust when running I have cleaned out the air filter and replaced the plugs but it made no difference.
Any help or advice would be much appreciated. and repaid with a few beers.
Thanks,
Mike

[David]

Have you considered using something like Forte Gas Treatment it may help.

Used DAE fuel system conditioner on a TB'ers bike recently and it was successful.

Is the fuel filter in the tank and/or in line clean?

[maverick]

Sounds like the carbs need at best a proper setup, fuel mixture, fuel level, at worst full strip and clean inspected for wear and then setup. If you have a workshop manual its normally quite easy to follow just can be quite time consuming.

First things i would check would be mixture screws, in the manual i think its called the pilot airscrew, these normally have a base setting like 1.5 to 2 turns out depending on bike, but it gets messed with quite a lot, to far out and it will give most of the symptoms your describing.

The next would be the fuel level in the float chamber, quite easily checked with the carbs on the bike with a piece of clear plastic hose. Usually find this procedure detailed in the workshop manual.

[Ballast]

Thanks Maverick, I have got the haynes manual and will have a look into what you suggested. Hopefully work is starting to die off a bit, 66 hour weeks dont leave much time for fiddling with the oily bits.

[Ballast]

right, got the tank off, thought I would check the mixture screws but they are not there. What I mean is, they are not where they are in the manual. I have since found out it is a jap import which is not covered by the haynes manual. I also found out it has reduced power in Japan, approx 77 instead of 106bhp. Anyway, back to the problem, is it possible that the mixture is fixed on a jap bike because of the stricter laws? if so any more ideas would be appreciated.

[bucko]

what bike is it?the mixture/air screws are normally coverd by a small brass blanking cover,you got any pics of your carbs?

[muzzasv]

Had a look on the old carbs I had for it looks like the screws are in the air inlet funnel on the opposite side of the bypass looks like it only adjusts the pilot jet though which I believe controls low and midrange which would explain why the bike is running poor at low rpm and picking up again at high rpm. If you want I can drop this set of carbs in for you sometime and have a look over it with you

[loneranger]

if it is possible i would remove the carbs then find the mix screws ,probably under grey caps .
dot mark with pen or similar, position of screw first .then wind clockwise to close .counting turn as accurately as poss (thats your factory set you need that later) then strip carbs clean thoroughly check choke device fitted replace any o rings if no smooth movement,check any diaphragms for pinholes or tears.replace any iffy bits. replace carbs and sync throttle slides, reset factory setting on idle/mix screws .remember the factory set mix stays the same through the rev range .so too week and you will burn things to rich and it will splutter a bit .best kept original jap spec you will prob have similar torque anyway. Good luck as with most things easier said than done

[Ballast]

Bucko, its a 1989 fzr 750.

Luke, that would be great if you have the time, do you still have my number? Have you changed the carbs, or did you get another set to try?

Loneranger, most of what you said went straight over my head. I have some experience with mechanics, but stripping carbs seems very complex, there seems like a hell or a lot to screw up.

[muzzasv]

Yeah the bloke I got it off told me when he had it in a garage that the bloke told him the set that were on it were screwed so he bought another set which I then fitted. When I put them on I checked they were the same and they looked identical and no i havnt got it bud I'm off to Norfolk tonight for a few days so wouldn't be able to get them to you till the weekend unless your at the pitstop later I could take them with me

[JP]

My VFR400 1989 Jap import was running a bit ruff (flat spots etc) So i replaced the main jets from 110 to 120 jets. Made the bike run far better. The bike was also restricted but only for top speed by an electronic tag in the speedo housing (to 110mph) I purchased a small black box off ebay that wired in and did away with this restriction (obviously i dont know if it works as i dont go that fast) but its nice to know my rear cylinders wont just cut out if i brake the 110mph barrier.

seems unusual the bike is BHP restricted? Have you looked to see if they do full kits to replace it for derestriction (all jets, setting etc?) ebay might do them. will probably make the bike run better too

[loneranger]

Apr 12, 2011 5:24:53 GMT Ballast said:

Bucko, its a 1989 fzr 750.

Luke, that would be great if you have the time, do you still have my number? Have you changed the carbs, or did you get another set to try?

Loneranger, most of what you said went straight over my head. I have some experience with mechanics, but stripping carbs seems very complex, there seems like a hell or a lot to screw up.

Sorry mate i had it in my head it was a honda v twin, personly with a multiple set up i,d be inclined to put it in with one of the site sponsers who has all the right gear and specs for it
regards Dave

[bucko]

Apr 12, 2011 5:24:53 GMT Ballast said:

Bucko, its a 1989 fzr 750.

Luke, that would be great if you have the time, do you still have my number? Have you changed the carbs, or did you get another set to try?

Loneranger, most of what you said went straight over my head. I have some experience with mechanics, but stripping carbs seems very complex, there seems like a hell or a lot to screw up.

hey what a coincidence,i used to have a 88 fzr750! has the bike been stood a while?it sounds to me like the carbs are gummed up due to stale petrol/crap in them,they,l need a good clean out,not that hard a job if you have a manual and a bit of patience and loads of carb cleaner ;D ,or find someone with an ultrasonic bath, makes the job loads easier! changing your main jet will not help the bike start any better,its your pilots that do that job! steve

[Ballast]

Apr 12, 2011 9:48:38 GMT loneranger said:

Apr 12, 2011 5:24:53 GMT Ballast said:

Bucko, its a 1989 fzr 750.

Luke, that would be great if you have the time, do you still have my number? Have you changed the carbs, or did you get another set to try?

Loneranger, most of what you said went straight over my head. I have some experience with mechanics, but stripping carbs seems very complex, there seems like a hell or a lot to screw up.

Sorry mate i had it in my head it was a honda v twin, personly with a multiple set up i,d be inclined to put it in with one of the site sponsers who has all the right gear and specs for it
regards Dave

No problem dave, the Honda is my main bike, I bought the FZR as a play time bike for if I ever manage to get out of the house without my daughter catching me.

Luke, I will not get to pitstop tonight, just got in from work. I will text you my number, if you ring or text me when its a good time for you over the weekend, I will pop over cheers.

Looks like I will have to bite the bullet and get them stripped down, it will be an experience if nothing else.
Thanks for all the advice,
Mike

[Gonzos Kustom Paint Shop]

i have a nice set!!

[muzzasv]

Didn't get you number bud but I should be in all day saturday